not mm realated BUT.. help!!!

[The new guy]

hey guys i know it's not ebmm realeted but
i have this q for you guys

i have that pre amp floor pedal made by hughes & kettnar called "tubeman"
i was wondering:

1.when do you know when you have to replace the little tube inside?
2.what kind of tube is it ? is it a regular ore tube like those onses thats in side my tube amp?
becouse when i look at the inside of it , it does not look like an ordinary ax7 tube
or am i just wrong maybe?

any way thanks for the replies to come!!!!

 

[Thirdpole]

It's a 12AX7 tube !

These preamp tubes last very very long ... 10-20-30 years without problems. You only need to replace them when they begin to have problems (making weird noises !)

http://www.hughes-and-kettner.com/products.php?mode=doc&id=11

Great preamp BTW !

 

[Tim O'Sullivan]

I would only change a pre amp valve when it goes microphonic.

 

[PrpaLe]

Original tube in H & K Tubeman is Ruby 12ax7